Kyle Kondik is managing editor of Sabato’s Crystal Ball, a nonpartisan political newsletter produced by the University of Virginia Center for Politics. He also directs the center’s Washington, D.C., office.

Geoffrey Skelley is associate editor at Sabato’s Crystal Ball.

Larry J. Sabato is university professor of politics and director of the University of Virginia Center for Politics, which publishes the online, free Crystal Ball politics newsletter every Thursday, and a contributing editor at Politico Magazine. His most recent book is The Kennedy Half-Century: The Presidency, Assassination, and Lasting Legacy of John F. Kennedy.

(5) Only a small number of House and Senate incumbents typically lose renomination every cycle—just 2 percent in the House, and 5 percent in the Senate, since World War II. So far this year, 273 of 275 House incumbents (99 percent) and all 18 of 18 Senate incumbents (100 percent) who sought another term have won renomination. So the theory of an anti-incumbent wave, so prominent after Cantor’s loss, collides with the cold facts. Anti-establishment forces in the GOP might still go after Sens. Pat Roberts of Kansas and Lamar Alexander of Tennessee, but their opponents are weaker than McDaniel. Cochran was very clearly the most vulnerable Republican Senate incumbent in this year’s primary season, and he has survived, albeit just barely.

(6) Despite their perfect record in Senate primaries so far this cycle, some Senate incumbents on the Republican side are having a harder time this year than they are used to. Cochran was forced into a runoff that he barely won. Republican Sens. John Cornyn of Texas, Lindsey Graham of South Carolina and Mitch McConnell of Kentucky all won around 60 percent of the vote or less in their primaries, and no one would call their opponents especially strong.

(7) There are intriguing “what ifs” in those other races: What if, say, Sen. Rand Paul had gone after his shadow foe from his 2010 primary, McConnell, and campaigned against the minority leader with his own candidate instead of providing him lukewarm support? Or suppose Cornyn had faced a more credible candidate than outgoing Rep. Steve Stockman and others? If Graham had squared off against one of the Tea Party congressmen in his state’s delegation, instead of a large and mostly unknown group of fractured challengers, he might have been forced into a runoff at the least. Perhaps the incumbent record would not be spotless.

(8) But this also hints at a bigger challenge for outsider forces in the Republican Party. The incumbents—at least the skilled ones—can co-opt their opponents and dissuade potential challengers from running. They work hard to keep the “what ifs” purely theoretical. Look at the recent vote for House majority leader: Rep. Kevin McCarthy of California worked the caucus and capitalized on his relationships with other members, making clear to possible opponents that he was going to win the job. The outsider Tea Party congressman who did challenge him, Rep. Raul Labrador of Idaho, openly disdained the insider politicking required to grab a job like House majority leader. Unless he acquires some of McCarthy’s skill set, he’ll remain a lonely voice. Anti-establishment forces can learn organizational lessons from the insiders they are trying to replace.

Mississippi’s remarkable Senate primary reminds us that every campaign is different, and sometimes a campaign can turn out to be unique. Incumbents who fall behind in the first primary rarely resurge in the runoff. Turnout usually falls in the runoff compared to the initial primary. A short runoff campaign often aids the candidate with momentum, in this case McDaniel. None of these things occurred in Mississippi this year. The voters turned the gloom-and-doom pre-election analysis about Cochran’s impending demise on its head.